Venomous Snakes of Nepal - BiK-F

Transcription

Venomous
Snakes of Nepal
A photographic guide
S.K. Sharma, D.P. Pandey, K.B. Shah, F. Tillack,
F. Chappuis, C.L. Thapa, E. Alirol & U. Kuch
If you are bitten by a snake
1.Don't panic. Most snakes are not dangerous, and even those that
are dangerously venomous often do not inject venom when they bite
a person.
2.Don't risk further bites or delay appropriate treatment by attempting
to search, capture or kill the snake. However, if the snake is already
killed, it should be carried safely along with the patient to the treatment
centre for identification.
3.Immobilize the bitten limb with a splint or sling and keep it still.
4.Don't run. If possible, let others carry you immediately (preferably by
motor vehicle) to the nearest health centre where anti-snake venom
serum is available. Using a motorcycle will help to save time.
5.Don't cut, burn or suck the bite site or the bitten body part.
6.Don't use herbs, chemicals, ice/cool packs or electric shocks.
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8;]sf] 7fpFdf k;fpFb}gg\ .
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klxrfgsf] nflu d/]sf] ;k{nfO{ lj/fdL;Fu} pkrf/s]Gb|df ;'/lIft tj/n] n}hfg'xf];\ .
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/ To;nfO{ :yL/ /fVg'xf];\ .
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k|lt/f]wfTds cf}iflw_ pknAw x'g] glhs}sf] :jf:Yo s]Gb|df n}hfg nufpg'xf];\ .
df]6/;fOsnsf] k|of]un] ;do arfpg ;xof]u ug]{ 5 .
%_ljiffn' ;k{n] 8;]sf] 7fpFdf sf6\g], r':g] / cfuf]n] 8fDg] sfd gu{g'xf];\ .
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pkrf/ ug]{ sfd gu{g'xf];\ .
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*_k|f/lDes cj:yfdf v';f{gL vfP/ ;k{n] 8;]sf] yfxf x'Fb}g, o;n] t k]6 kf]n]/
pkrf/df emg afwf k'¥ofpF5 .
(_s'v'/fsf] dnåf/ 8;]sf] 7fpFdf nufpFbf ljif r':5 eGg] wf/0ff unt xf] .
Venomous Snakes of Nepal
A PHOTOGRAPHIC GUIDE
S.K. SHARMA, D.P. PANDEY, K.B. SHAH, F. TILLACK,
F. CHAPPUIS, C.L. THAPA, E. ALIROL & U. KUCH
with additional photographs by
H.S. Bawaskar, A. Captain, M.A.W. Chowdhury,
S. Dalvi, W. Grossmann, A. Gumprecht,
V.K. Mistry, N.L. Orlov, H.H. Schleich,
S. Thakur, D.A. Warrell
Authors
Prof. Sanjib Kumar Sharma, B.P. Koirala Institute of Health Sciences (Dharan, Nepal)
Mr. Deb Prasad Pandey, Biodiversity and Climate Research Centre (Frankfurt am
Main, Germany)
Prof. Karan Bahadur Shah, Natural History Museum, Tribhuvan University
(Kathmandu, Nepal)
Mr. Frank Tillack, Museum für Naturkunde (Berlin, Germany)
Prof. François Chappuis, Geneva University Hospitals (Geneva, Switzerland)
Dr. Chhabilal Thapa, Sindhuli District Hospital (Sindhuli, Nepal)
Dr. Emilie Alirol, Geneva University Hospitals (Geneva, Switzerland)
Dr. Ulrich Kuch, Biodiversity and Climate Research Centre (Frankfurt am Main,
Germany), e-mail: [email protected]
Published by
B.P. Koirala Institute of Health Sciences
Dharan, Nepal
First edition, February 2013
© by the authors
The role of the Embassy of Switzerland in Nepal/Swiss Agency for Development and
Cooperation (SDC) Nepal in providing financial support for the publication of this
book is gratefully acknowledged. The technical support provided by Mr. Dandi Ram
Bishwakarma, Senior Program Officer (Swiss Embassy/SDC) and Mr. Mamit Rai (Snake
Bite Project, B.P. Koirala Institute of Health Sciences, Dharan) during the publication
process of this book is highly appreciated.
The material in this publication may not be reproduced in whole or in part and in any form
without prior written permission from the copyright holders. This book is a non-commercial,
not for profit publication. Its sale or other commercial distribution is not allowed.
Free electronic copies of this book may be downloaded from the web site of the
Biodiversity and Climate Research Centre (BiK-F) via the following link:
http://tinyurl.com/nepalsnakes
ISBN number : 978-9937-2-6003-9
Number of copies : 1,500
Designed and printed by : PowerComm, Sanepa, Lalitpur, Phone No. 01-5552987
Cover photo : Spectacled Cobra (Naja naja). Photo by U. Kuch.
7 February 2013
Foreword
I am pleased to introduce and welcome this guidebook on the venomous snakes of
Nepal. This important new book demonstrates with excellent photographs, the colourful natural
beauty and biodiversity heritage represented by – cobras, kraits, coral snakes and vipers.
Although snakes are widely recognized as farmers’ friends because they efficiently control
rodent populations, their bites also cause immense suffering among the rural populations of South
Asia. This is also the case in Nepal where snake bites have always been a great public health
concern in the lowlands. However, due to global warming, some venomous snakes of our lowland
regions could in the future also cause problems in the hills where people may not yet be prepared
for this. Thus, we wish this book to be distributed and used in the entire country.
The Government of Nepal through its Ministry of Health and Population has responded to
the needs of snake bite patients in Nepal by distributing life-saving anti-snake venom immunoglobulin
drugs, free of charge to hospitals and snake bite treatment centres, and by imparting training for
health professionals in the country. We are fully committed to continuing and expanding these
activities. It is also recognized that several aspects of the prevention and clinical management of
snake bite in Nepal requires further investigations and that progress in scientific research on these
matters may in the future lead to changes in the guidelines.
In this sense, it is our great pleasure to receive this book as another example for the
outstanding success of international collaboration between medical doctors and biologists from
Nepal, Switzerland and Germany whose tireless efforts have contributed so much to improve our
knowledge and treatment of overlooked and neglected snake bite disease.
It is our sincere expectation that the diffusion of the information provided in this book will
contribute to the environmental and health education of the people and to improve the situation of the
snake bite in Nepal. We also express our hope that the publication of this book will increase
awareness and stimulate much needed additional scientific research on this subject.
(Dr. Praveen Mishra)
Secretary
Foreword
Since ancient times, snakes have been worshipped, feared, or loathed in Nepalese
society. Especially cobras appear in many tales and myths and are regarded as sacred in different
religions and cultures. Indeed, snakes play a very important role in agriculture, being the best
natural controllers of rats and mice and therefore securing harvests and income, and limiting the
spread of rodent-borne diseases.
Unfortunately, snakes at the same time are also a painful reality in the daily life of millions
of villagers in Nepal where envenoming following snake bites is a very common and serious public
health problem. Throughout the South Asian region, lack of knowledge about venomous snakes,
first aid measures and medical treatment, along with limited access to quality care and specific
essential medicines, result in high morbidity and mortality.
Here, the Embassy of Switzerland in Nepal and the Swiss Agency for Development and
Cooperation SDC present for the first time in Nepal a photographic guidebook that is entirely
devoted to the venomous snakes of this country and the important questions of how they can
be distinguished from each other and from harmless non-venomous snakes, how bites by such
snakes can be avoided, and what can be done to obtain the best treatment result if one is bitten.
By sponsoring the publication and distribution of this booklet, prepared by a team of
experts from Nepal, Switzerland and Germany, we hope to increase the knowledge of the rich
biodiversity of Nepal and the respect for this ecologically, economically and medically important
group of animals. Better knowledge of snakes, their distribution, habitats and behaviour, and of
practicable ways of preventing their bites, is necessary to reduce the high number of snake bites
in Nepal. At the same time, knowing what to do and what not to do after a snake bite is crucial for
reducing snake bite morbidity and mortality. Finally, in the snake bite clinic or hospital, knowing
which species of snake had caused the bite can play a very important role for treatment decisions.
We hope that this book will serve all these purposes.
Numerous aspects of the venomous snakes of Nepal, including their geographical
distribution and diversity, are still unknown. Almost none of their venoms have been analyzed
scientifically, and from some species even not a single proven case of envenoming is known.
Hopefully scientific research in this field will be dynamic enough to generate new data soon. Then,
in a few years this book may be updated for the benefit of the Nepali people.
Thomas Gass
Ambassador and SDC Country Director
Embassy of Switzerland in Nepal
CONTENTS
What is a snake?
1
Which other animals look similar to snakes?
1
How many different species of snake are there?
3
Which snakes are dangerous for humans?
3
How can dangerously venomous snakes be distinguished
from others? 5
Green snakes Snakes with blotched colour pattern
Other snakes that look like vipers
Rat snakes and racers
Water snakes
Wolf and Kukri snakes
Uniformly black and brown snakes 5
9
13
15
17
18
20
How many snake species occur in Nepal, and how many
of these are dangerous?
23
23
Kraits, cobras, king cobras and coral snakes (family Elapidae)
Bungarus bungaroides
Bungarus caeruleus
Bungarus fasciatus
Bungarus lividus
Bungarus niger
Bungarus walli
Naja naja
Naja kaouthia
Ophiophagus hannah
Sinomicrurus macclellandi univirgatus 24
27
29
32
34
36
38
40
42
44
Vipers and pit vipers (family Viperidae)
47
Daboia russelii
48
Gloydius himalayanus
50
Himalayophis tibetanus
52
Ovophis monticola
56
Protobothrops sp.59
Trimeresurus cf. albolabris
61
Trimeresurus septentrionalis
63
Other venomous snakes
65
Rhabdophis subminiatus
66
Management of snake bite
68
Introduction
Clinical features of snake bite
68
68
68
69
Cobra and krait bites
Viper bites
First aid
Management at the health centre
70
70
70
71
71
Immediate management
Indications for antivenom injection
Dose of antivenom
Prevention of snake bite
Selected additional information resources
71
75
U. Kuch
Fig. 1. Spectacled Cobra (Naja naja).
What is a snake?
Snakes are limbless reptiles having an elongated body covered with
scales which are arranged in rows. The form, structure and arrangement
of these body scales are important for snake species identification.
Snakes are different from birds and mammals in many ways. They are
vertebrate animals too (with an inner skeleton), but birds and mammals
are warm-blooded animals which can maintain their body temperature
stable despite changing temperatures in the environment. However,
snakes are cold-blooded animals and under normal circumstances they
have to regulate their body temperature by choosing appropriate places
in their environment (e.g., by sun bathing or hiding in holes), so they are
very sensitive to weather and climatic changes and other ecological or
environmental conditions.
Which other animals look similar to snakes?
Superficially, some snakes look similar to certain fishes, e.g., eels.
However, fishes have gills and typically use these for breathing, whereas
snakes breathe via lungs throughout their life. Also, many eels move in the
water with the help of fins (which snakes do not have), and they do not
have scales on the body like snakes.
Earthworms are sometimes confused with snakes but they have no interior
skeleton of bones and no protective scales covering the body; instead
they have rings on their body which snakes do not have. So-called worm
or blind snakes that often are of similar size and shape as earthworms do
1
Fig. 2. Common/Brahminy Worm Snake (Ramphotyphlops braminus) from Kapilvastu District, Nepal.
K. B. Shah
have these scales (just very small and shiny ones, see Fig. 2), and even
poorly developed eyes visible as dark spots on the head.
Limbless amphibians also have distinct rings on their bodies, but they have a
bony skeleton, and visible eyes on the head. Unlike frogs and salamanders,
limbless amphibians have body scales that are embedded in the skin along
the ring grooves.
From lizards, snakes differ in various ways. Snakes do not have legs, but
lizards typically have legs. Snakes have no external ears, but lizards have
external ear openings that are usually well visible. Most lizards, including those
species that have a snake-like body without limbs, have moveable eyelids so
they can close their eyes. In snakes, there are no moveable eyelids. Instead,
the eye is covered by a transparent disc-like scale for protection. The same
type of eye without eyelid is also seen in certain lizards like the common house
gecko. Finally, snakes have tongues with forked tips. As they use their tongue
to detect odours in their environment, having a forked tongue allows them
to determine if a scent trace on the ground that was made by a prey animal
turned to the left or right side, so they can follow it with greater precision.
Among the common lizards of Nepal, monitor lizards (family Varanidae) also
have tongues with forked tips, but these large lizards have four very well
developed legs, well visible external ears, and moveable eyelids.
2
How many different species of snake are there?
There are more than 3400 different species of snake on earth. Snakes can
be found on all continents except Antarctica, and they have conquered the
most divergent environments from the mountains of the Himalayas to the
coral reefs of the Pacific Ocean. There are snakes that spend all of their life
in the water, others that live underground in holes and burrows that they or
other animals have dug, and yet others that spend their lives high up in the
canopy of trees. Most snakes reproduce by laying eggs but some species
give birth to fully developed young. Certain species of snake like pythons
or the king cobra even guard and protect their eggs. Snakes exclusively
eat other animals, and many species are capable of swallowing prey that
is very big or bulky compared to their own body. By controlling the number
of other animal species, and by serving as food to others like birds of prey
and other predators (e.g., mongoose), snakes play an important role in the
natural ecosystems and artificial agro-ecosystems. For farmers, snakes are
very useful because they help to control rodent populations by eating the rats
and mice that would otherwise damage crops or eat stored food.
Which snakes are dangerous for humans?
Most species of snake are harmless for humans. Many have no venom at all,
and they either kill their prey by constriction or by pressing it to the ground,
or simply swallow it alive. Many others produce secretions in specialized
oral glands that help them to immobilize, kill and/or digest their prey and
to act against harmful bacteria. From a biological point of view, these oral
gland secretions are usually called venoms (and the glands in which they are
produced, venom glands) if the snakes use them to quickly immobilize or
kill their natural prey. This is usually achieved if the snakes do not only have
toxic oral gland secretions, but also an effective venom apparatus to deliver
these into their prey or enemy. The teeth of snakes play a key role in this.
The most primitive type of dentition of snakes consists of teeth that are of
similar size and shape anywhere in the mouth. Many snake species have
a more differentiated dentition in which certain teeth are longer and have
blade-like ridges or grooves. These can facilitate the penetration of the teeth
into the prey and/or the application of toxic oral gland secretions. A large
number of snake species has such enlarged teeth in the back of the upper
3
jaw. Under usual circumstances, these so-called "rear-fanged snakes" cannot
effectively apply their toxic oral gland secretions to human bite victims.
The most sophisticated and effective venom apparatus, the so-called
front-fanged venom apparatus, is composed of the following parts:
1.Two much enlarged teeth for venom injection (also known as fangs) in
the front of the upper jaw of the mouth.
Fig. 3. Green pit viper (Trimeresurus sp.) showing the venom fangs.
U. Kuch
2. A venom duct that connects each fang with one well-developed venom
gland located behind the eye on each side of the head.
Worldwide less than 700 species of snake have this type of venom
apparatus, and only a fraction of these is actually of significant medical
concern.
4
How can dangerously venomous snakes be distinguished
from others?
Recognizing which snake is dangerously venomous and which one is not is
often difficult for non-experts. However, there are certain external features
that can be very useful for distinguishing dangerous species from harmless
ones even if they look superficially similar. In this section we will discuss and
illustrate some of the most relevant ones in the context of Nepal.
Green snakes
In Nepal there are several species of snake with variable shades of light
or dark green colouration, but only some of these are dangerous. Some
important characteristics can be used to distinguish these:
F. Tillack
1.In Nepal, green snakes with large scales on top of the head and a
pupil of the eye that is round in daylight are harmless. For example, the
non-venomous snake Orthriophis hodgsonii (Fig. 4) is often confused
with venomous pit vipers in the hills of Nepal.
Fig. 4. Juvenile specimen of Orthriophis hodgsonii from central Nepal. Note the few very large scales on
top of the head and the round pupil that distinguish this non-venomous species from pit vipers with similar
colour pattern.
2.Green snakes whose pupil of the eye is horizontal and whose snout is
very long and pointed (see Fig. 5) are only mildly venomous. The head
of these snakes is also very long and thin, not very distinct from the
5
F. Tillack
neck, and covered on top by large scales. When disturbed, these snakes
(e.g., Ahaetulla nasuta) show their opened mouth to discourage their enemy.
Fig. 5. Ahaetulla nasuta. This mildly venomous species of "green snake" is easily distinguished from
other snakes by its long pointed snout and horizontal pupil.
F. Tillack
3.Green species of the genus of cat-eyed snakes (Boiga spp.) are more
similar to the dangerous green pit vipers because their pupils are vertical
in daylight just like those of the pit vipers. However, green cat-eyed
snakes like the Boiga cyanea on the photo below have no pit organ
between nostril and eye (this is present in all pit vipers), and they have
only a few large scales on top of the head (versus many small scales
in the case of green pit vipers). Like Ahaetulla nasuta, Boiga species
are mildly venomous, having enlarged teeth in the back of their mouth
which they use to inject venom into their prey, but no cases of human
envenoming from their bites have become known in Nepal.
Fig. 6. The mildly venomous Green Cat-eyed Snake (Boiga cyanea) is similar to the dangerously
venomous green pit vipers in having a pupil that is vertical in light, but differs from them in having very
large scales on top of the head and lacking venom fangs in the front of the mouth.
6
A
B
F. Tillack
Fig. 7. (A) Adult female Green Cat-eyed Snake (Boiga cyanea) from Suratthani, Thailand. (B) Juvenile
of the same species from Ban Na San, Suratthani, Thailand. Like several species of green snake,
B. cyanea undergo a colour change as they grow.
F. Tillack
4.Green pit vipers are the only group of dangerously venomous snakes
with green colouration in Nepal. There are several different species
of green pit vipers in Nepal, and some have particular distributions
according to altitude or vegetation. Most of them are difficult to
distinguish from each other even for zoologists, but they all differ from
their non-venomous or mildly venomous lookalikes in having a pit organ
between the eye and the nostril (indicated by the red arrow on Fig. 8),
Fig. 8. Kramer's Green Pit Viper (Trimeresurus septentrionalis) from Nepal showing the location of the
opening of the pit organ between the eye and the nostril (arrow), numerous small scales on top of the
head, and the yellow eye with a pupil that is vertical in light. These features are characteristic for all "green
pit vipers" in Nepal although the colour of the eye and the head can vary according to the species or sex
of the snake.
7
numerous small scales on top of the head (see Fig. 9), including the front,
a head that is flat, triangular or heart-shaped and very distinct from the
neck, and a pupil that is vertical in light. In addition, like all vipers these
snakes have a pair of very long hollow fangs in the front of their upper
jaw that can be folded back when not in use and erected for biting, and
which function like injection needles to inoculate venom into their prey
and enemies (see Fig. 3).
A. Gumprecht, specimen courtesy of Fuhlrott Museum
Although bites by green pit vipers usually cause mild envenoming only
if compared to kraits and cobras, and fatalities are rare, these snakes
appear to cause a large proportion of all cases of snake bite envenoming
in Nepal. Envenoming by green pit vipers is very painful and may be
followed by complications especially in the case of children. Loss of
body fluids into massively swollen extremities can lead to hypovolaemic
shock and requires proper replacement; destruction of local tissue by
the venom as well as non-clotting blood and bleeding may also occur.
There is presently no specific antivenom to treat green pit viper bites
in Nepal. There is no evidence that the polyvalent snake antivenoms
from India have any effect on green pit viper venoms. A special green
pit viper antivenom is produced in Thailand but whether it is effective
against the venoms of the green pit viper species of Nepal still needs to
be determined.
Fig. 9. Head of an adult White-lipped Pit Viper (Trimeresurus cf. albolabris) from southern Nepal, viewed
from above. Note the numerous small scales covering the head.
8
Snakes with blotched colour pattern
F. Tillack
In Nepal, two species of python may be confused with some venomous
snakes: The Burmese Python (Python bivittatus; see Fig. 10) and the
Indian Rock Python (Python molurus, see Fig. 11). Adult pythons are
much longer (3 to over 7 m) than any of the vipers in Nepal, but smaller
ones may look quite similar at first sight. Like pit vipers, pythons have
visible heat-sensitive pit organs, but in the case of these pythons they are
located on the snout tip and the first two upper lip scales, actually below
the nostril, not between the eye and the nostril as in pit vipers. Also, the
Fig. 10. Burmese Python (Python bivittatus). The position of the heat sensitive pit organs of the python is
indicated by the large red circles, that of the nostril by the small red circle.
pythons have smooth and shiny scales on their body (Russell's Viper and
pit vipers have keeled scales) and few large scales on top of the head
(small and numerous in Russell's Viper and all pit vipers in Nepal except
Gloydius himalayanus). Finally, the colour pattern of pythons and Russell's
Viper is different: The pythons have asymmetrical dark brown blotches
that are often bordered with black, but Russell's Viper has symmetrical
blotches that are round or oval in shape and with pointed ends. Pythons
have no venom but kill their prey by constriction. If annoyed, they can
deliver painful bites. Bites by large pythons can produce wounds that are
similar to superficial cuts by a knife and may require surgical treatment.
9
Fig. 11. Indian Rock Python (Python molurus).
F. Tillack
Fig. 12. Juvenile Russell's Viper (Daboia
russelii) from Maharashtra, India.
10
D. A. Warrell
A. Captain/S. Thakur
Russell's Viper (Daboia russelii, Fig. 12 and 13) is the only species of "true" viper
(a viper without pit organ) that is known from Nepal. Wherever it occurs,
Russell's Viper is one of the most dangerous venomous snakes. In Nepal,
it has so far been found in a few southern Terai districts only. Its head is
Fig. 13. Adult Russell's Viper (Daboia russelii) from
India, photographed at Madras Snake Park.
covered by numerous small scales. Its colour pattern with symmetrical,
round or oval to leaf-shaped blotches on the body also distinguishes it from
pythons and pit vipers, and from the sand boa. Note also the much longer
tail of Russell's Viper (Fig. 13) if compared to that of the sand boa (Fig. 14).
Fig. 14. Common Sand Boa (Gongylophis conicus).
U. Kuch
The Common Sand Boa (Gongylophis conicus, Fig. 14 and 15) is a small
non-venomous snake that is often confused with vipers. Snake charmers often
use these harmless snakes in their shows pretending that they are dangerous
vipers. In fact, like Russell's Viper, sand boas have numerous small scales on
top of the head and a pupil that is vertical in light. However, the neck of sand
boas is much thicker (in vipers the head is very distinct from the slender neck),
sand boas have a very short tail, much shorter and more strongly keeled body
scales, and a different, irregular pattern of dark blotches on the back. Sand
boas usually grow up to 50-60 cm, rarely up to 1 m.
11
Fig. 16. John's Sand Boa (Eryx johnii).
12
K.B. Shah
Fig. 15. Common Sand Boa (Gongylophis conicus), detailed view of the head and neck.
U. Kuch
Other snakes that look like vipers
In Nepal there are several species of snake that have a very similar
appearance to the highly venomous pit vipers and Russell's Viper. Some
of them have enlarged teeth in the front or back of their mouth and some
are mildly venomous, but no cases of human envenoming have been
reported. In contrast, pit vipers and Russell's Viper have very long venom
fangs in the front of their mouth which can be erected for biting and folded
back when the mouth is closed.
Fig. 17. Mock Viper (Psammodynastes pulverulentus),
adult female from Cameron Highlands, Pahang
State, West Malaysia, 1646 m above sea level.
This non-venomous snake has rather large teeth in
the upper and lower parts of the front of its mouth
which it uses to grasp hard-bodied lizard prey.
F. Tillack
F. Tillack
None of these non-venomous viper lookalikes has a pit organ between eye
and nostril. This distinguishes them from all the pit vipers. The pit organ
of the latter (see Fig. 8 and 19) is used for thermoreception, especially to
detect warm-blooded prey or enemies in the environment, even in total
darkness. A very species-rich group of vipers, known to zoologists as the
subfamily Crotalinae, is called pit vipers because of this organ. All known
vipers in Nepal except Russell's Viper are pit vipers. Most of the pit vipers
give birth to fully developed young, but some like Ovophis monticola (see
Fig. 92) lay eggs which the mother will guard.
Fig. 18. Common Cat Snake (Boiga trigonata).
This mildly venomous species has enlarged teeth
in the back of its mouth.
13
F. Tillack
Fig. 19. Head of a Mountain Pit Viper (Ovophis
monticola) in side view. The small red circle marks the
position of the nostril, the large red circle that of the pit
organ, halfway between nostril and eye.
The Himalayan Pit Viper
(Gloydius himalayanus, see
Fig. 20) is the only viper in
Nepal that has few very large
scales on top of the head like
some of the non-venomous or
mildly venomous lookalikes of
vipers.
However,
it
is
distinguished from all of
these by having a pit organ,
and from most also by its
distinct dark stripe that runs
from the eye to the corner of
the mouth.
F. Tillack
The Mock Viper (Psammodynastes pulverulentus; see Fig. 17) and the
Common Cat Snake (Boiga trigonata; see Fig. 18) look very similar to some
vipers and pit vipers as far as their colour pattern, eyes and head shape are
concerned. However, the top of their heads is covered with few very large
scales. This distinguishes them from Russell's Viper and from almost all pit
vipers in Nepal, which have numerous small scales on top of the head. One
exception is the Himalayan Pit Viper (Gloydius himalayanus, see Fig. 20).
Fig. 20. Himalayan Pit Viper (Gloydius himalayanus), adult male from Kalopani, Mustang, Dhaulagiri,
Nepal, 2500 m above sea level.
14
Rat snakes and racers
Fig. 21. Head of an Indian Rat Snake (Ptyas mucosa).
Fig. 22. Head of a Spectacled Cobra (Naja naja).
U. Kuch
U. Kuch
There are several species of large, slender and fast-moving non-venomous
or mildly venomous snake in Nepal that are active by day, or around dusk
and dawn, and therefore often seen by people around their houses, in the
fields, or in the forests. Some of these are often confused with the highly
venomous cobras because they have a similar size and built, and because
they are ready to defend themselves by biting if they see no chance to flee.
Although some of them can produce very impressive hissing and growling
sounds, their defensive display is actually very different from that of cobras.
For example, cobras will spread the skin of their neck horizontally, displaying
dark round 'V' or 'Y' or 'O' shaped marks on their neck, and will usually raise
their forebody vertically off the ground, looking at their adversary (see Fig. 23).
Rat snakes and racers, on the other hand, inflate their neck and forebody by
inhaling air and extending their body in vertical direction (see Fig. 24). They also
stay closer to the ground, bringing their forebody into S-shaped positions that
will facilitate striking or darting off in an attempt to escape. Compared to cobras
they also have more slender and much longer heads and much larger eyes.
All of these snakes are very useful especially for farmers because they
help to control populations of mice and rats. Some species of rat snake
and racer kill their prey by constriction, others simply by pressing it
onto the ground. Some have been found to produce certain toxins
in their oral glands, but there has been no report of envenoming from
any of the rat snake and racer species that occur in Nepal. However,
15
F. Tillack
Fig. 23. Spectacled Cobra (Naja naja) viewed
from above, showing its typical defensive display
that includes a raised forebody, neck skin spread
to a "hood" with spectacle-shaped marks.
Fig. 25. Indian Rat Snake (Ptyas mucosa).
F. Tillack
U. Kuch
Fig. 24. Copper-headed Trinket Snake (Coelognathus
radiatus)
F. Tillack
when they feel cornered most will defend themselves by biting. As these
are large snakes that usually reach 1.5-2.5 m, sometimes even over
3 m, they can inflict painful and bleeding (but harmless) wounds which
should be treated like any other scratch wound.
Fig. 26. Indo-Chinese Rat Snake (Ptyas korros), subadult specimen from Suratthani, Nakhon Si
Thammarat, Thailand.
16
Water snakes
Fig. 27. Striped Keelback (Amphiesma stolatum).
Fig. 28. Striped Keelback (Amphiesma stolatum)
from Naudanda-Kaidala, Kaski, Gandaki, Nepal,
1300 m above sea level.
F. Tillack
U. Kuch
Water snakes that are common in and around rice/paddy fields and ponds are
very often seen by people and sometimes confused with venomous snakes.
The Striped Keelback (Amphiesma stolatum; see Fig. 27 and 28) is active by
day and rarely bites. It is easily recognized by its pattern of blotches on the
anterior body and distinct stripes on the posterior body and tail.
Fig. 29. Two Checkered Keelbacks (Xenochrophis piscator complex) from Bangladesh.
U. Kuch
The Checkered Keelback group (Xenochrophis piscator and closely related
species, see Fig. 29) comprises larger snakes that can grow to more than
1 m, are often very active at sunset or night, and will defend themselves readily
by biting when they are caught or stepped on. They are often mistaken for
cobras. As they are very common, they cause a large proportion of nonenvenoming snake bites in Nepal.
17
Fig. 30. Siebold's Water Snake (Ferania sieboldii).
F. Tillack
Siebold's Water Snake (Ferania sieboldii, see Fig. 30) is sometimes confused
with vipers or pit vipers, but in the areas where it lives, all of these have
small scales on top of the head (vs. large scales in Ferania). For its dark and
light pattern on the back it might also be mistaken for a krait, but in Ferania
all scales on the back are of similar size (those of the middle row are much
enlarged in kraits), and Ferania sieboldii has many more rows of scales around
the body than kraits (27-33, vs. 15-17 in most kraits).
Wolf and Kukri snakes
Looking similar to the highly dangerous kraits, the Common Wolf Snake
(Lycodon aulicus, see Fig. 31 and 32) belongs to those snakes that most
commonly enter human houses or even live there permanently. These
small snakes usually reach 40-80 cm and eat other small animals like
skinks, geckos and mice. As they are also active at night, have a somewhat
similar colour pattern and are usually quick to bite if they are touched
or handled, they are often confused with kraits like the Common Krait
(Bungarus caeruleus). However, the bites of Common Wolf Snakes are
harmless, so this species contributes a great part of those snake bites that
do not result in envenoming. In marked difference to kraits, the scales on
the back of wolf snakes are all of similar size and shape.
18
Fig. 31. Common Wolf Snake (Lycodon aulicus),
adult female caught in a shop in the centre of
Damak, Jhapa, Nepal.
F. Tillack
U. Kuch
Fig. 32. Common Wolf Snake (Lycodon aulicus),
adult female from Naudanda, Kaski, Gandaki,
Nepal, 1450 m above sea level.
U. Kuch
Another group of small snakes that are occasionally confused with kraits
or vipers are Kukri snakes (Oligodon arnensis; see Fig. 33). Their English
common name refers to the fact that they have very large, blade-like teeth
in their mouth. With these they can inflict painful bites. As there have
been reports in other countries about prolonged bleeding from such bite
wounds, caution is indicated. Kukri snakes differ from Russell's Viper and
pit vipers in having a pupil that is round in light, and large scales on top of
the head; from pit vipers also because they have no pit organ. They differ
from kraits in having scales on the back that are all of similar size and shape.
One species, Oligodon albocinctus, may be confused with MacClelland's
Coral Snake (Sinomicrurus macclellandi) due to their similar colour pattern,
however, the eye of the venomous coral snake is almost completely black
while that of the Kukri snake has a light ring around the pupil.
Fig. 33. Kukri Snake (Oligodon arnensis) from the campus of B.P. Koirala Institute of Health Sciences,
Dharan, Nepal.
19
Uniformly black and brown snakes
In Nepal, there is a number of species of smaller snakes that have a
uniformly black or brown colouration on the back side of their bodies
(often with lighter bellies) and that are not cobras or rat snakes. Many
of these are non-venomous or only mildly venomous and not dangerous
to humans, but some are highly dangerous venomous snakes so it is
important to recognize them.
F. Tillack
There are two different species of deadly venomous black krait found
in Nepal, the Greater Black Krait (Bungarus niger, see Fig. 34) and the
Lesser Black Krait (Bungarus lividus, see Fig. 35). Like all kraits, they
differ from most snakes in Nepal in having one row of hexagonal scales
along the middle of their back from neck to tail (on top of the vertebral
column, therefore also called vertebral scales) that are much larger than
the other scales on the back of their body.
Fig. 34. Greater Black Krait (Bungarus niger). Note that the scales along the back of the body (vertebral
scales) are much larger than the adjacent body scales. This is typical of all kraits except Bungarus lividus,
which has smaller vertebral scales. Like all kraits, these species are highly venomous.
20
U. Kuch
A
B
Fig. 35. (A and B) Head of a Lesser Black Krait (Bungarus lividus) in close-up view. Note the small eye,
pointed snout and head that is not distinct from the neck. The pupil of the eye is white because the snake
is a preserved museum specimen; in live snakes the eye appears like a small jet black bead.
A
B
Drawing modified from F. Wall (1908)
The black krait species Bungarus niger and Bungarus lividus differ in
the size of these enlarged scales. In Bungarus niger, they are very
large, like in all other species of krait. In Bungarus lividus, they are
only slightly larger than the bordering scales on the back of the body.
Fig. 36. Strongly enlarged vertebral scales on the back of Bungarus niger (and other kraits, A) and only
slightly enlarged vertebral scales of Bungarus lividus (B).
Some cat snakes in Nepal (e.g., Boiga ochracea, see Fig. 37) can have a
similar uniformly brown colouration and also have an enlarged row of scales
along the middle of their back. However, they can be distinguished from
kraits in having much larger eyes and a pupil that is easily visible and of vertical
shape in light. The eyes of black kraits are very small and appear black in life.
Cat snakes also differ from all kraits in Nepal except Bungarus bungaroides
in having paired (divided) scales on the lower side of the tail, and in having a
comparatively bigger head that is distinct from the slender neck. In addition,
cat snakes differ from kraits in having a body that appears laterally compressed
(vs. round or triangular in cross-section as in kraits).
21
Cat snakes are rear-fanged snakes that use enlarged teeth in the back
of their mouth to apply venom to their prey. The cat snake species in
Nepal are considered to be mildly venomous, and no cases of human
envenoming by them have been reported.
Fig. 37. Tawny Cat-eyed Snake (Boiga ochracea), subadult female from Naudanda-Serachaur, Kaski,
Gandaki, Nepal, 1300 m above sea level.
22
F. Tillack
The Tawny Cat Snake (Boiga ochracea) is widely distributed in the lowlands
and hills of Nepal and neighbouring countries. It is often reddish-brown,
yellowish-brown or even coral red, but darker specimens may be confused
with black kraits. Like kraits, it is active at night, but unlike kraits it mostly
climbs in house walls, bushes or shrubs where it preys on lizards, birds and
small mammals. Note the large eye with well visible vertical pupil.
How many snake species occur in Nepal, and how many
of these are dangerous?
So, far 89 species of snake have been recorded from Nepal, but the exact
number remains to be determined because large parts of the country
are still unexplored from a biological point of view, and some published
records of snake species that are difficult to identify require further
study and verification. Among this great diversity of snakes, we know
with certainty of 17 species of snake that occur in Nepal and have the
front-fanged type of venom apparatus and thus are considered to be
highly venomous and dangerous.
These snakes can be subdivided further into two groups:
Kraits, cobras, king cobras and coral snakes (family Elapidae)
U. Kuch
Snakes of this group have two
relatively short fangs that are
firmly attached and immobile,
one on each side of the
upper front of their mouth (on
the maxillary bone). Although
short, their teeth have deep
grooves on the outside that
efficiently serve as canals to
transport venom into the prey
or enemy. Some of these
snakes, especially kraits,
have very small fangs. Their
bites often do not result in
visible bite marks or bleeding
wounds. However, this does Fig. 38. Spectacled Cobra (Naja naja) from Damak, Nepal.
not help to predict the severity of envenoming. In a krait bite, even if
there is no visible bite mark and no health problem at all during the
first few hours, it is still possible that life-threatening envenoming
like respiratory paralysis may develop after up to 12 hours. Thus, all
(suspected) snake bites should be observed in hospital for 24 hours
even if there are no signs of illness at the beginning.
23
Bungarus bungaroides
Himalayan Krait (English), Pahadi Karet, Himali Karet (Nepali)
S. Dalvi
Identification: Usually 1-1.5 m long, hatchlings about 30 cm. Shiny
black, brownish black or grey body and tail with very narrow white or
yellowish rings. Light rings often much obscured in large adults, less
than one scale wide on body but extending completely across belly
where they are broader. Tail tip pointed. Fifteen rows of scales across
back, scales along vertebral ridge much larger than bordering scales.
Scales on lower side of tail divided.
Fig. 39. Himalayan Krait (Bungarus bungaroides) from Eagle Nest, Arunachal Pradesh, India. Note the
light lines on the head which are typical of young individuals of this species.
Distribution and habitat: Likely throughout the lowlands and lower
mountains of eastern Nepal. Elsewhere, from the Brahmaputra Valley of
Tibet, Bhutan and north-eastern India to northern Myanmar. Known from
open forests, agricultural lands and residential areas between 200 and
1500 m altitude.
Medical importance and behaviour: Very little is known about this rarely
encountered snake. Surprisingly for kraits, there have been a couple of
observations of this species that suggested activity during the day. There
have been no identified bites by this species which is likely often confused
with Bungarus caeruleus. It should be expected that envenoming by this
species can cause death in a short time.
24
Fig. 41. Large adult Himalayan Krait (Bungarus bungaroides) from
Eagle's Nest, Arunachal Pradesh, India with uniformly dark grey to
black anterior body.
V. K. Mistry
Fig. 40. Lower side of tail of
the Himalayan Krait (Bungarus
bungaroides) showing light rings
and divided subcaudal scales.
V. K. Mistry
S. Dalvi
Venom effects: In the absence of studies on the venom of B. bungaroides
it should be expected that it is similar to other krait venoms in causing
progressive paralysis of the peripheral nervous system, leading to
respiratory paralysis and death due to asphyxia, and possibly systemic
muscle damage with myoglobinuria, acute renal failure and hyperkalaemia.
Thus, both neurotoxic and myotoxic envenoming and their complications
should be anticipated when treating a patient bitten by this snake.
Fig. 42. Enlarged row of scales along vertebral ridge and light rings across posterior body of the same
snake as in Fig. 41.
25
S. Dalvi
S. Dalvi
Fig. 43. Large adult Himalayan Krait (Bungarus bungaroides; same snake as in Fig. 41); note light rings
across body.
Fig. 44. Large adult Himalayan Krait (Bungarus bungaroides; same snake as in Fig. 41); note light rings
across the dark belly.
26
Bungarus caeruleus
Common Krait (English), Seto-kalo Chure Sarpa, Gadaich, Chure Sarpa (Nepali)
Fig. 45. Adult Common Krait (Bungarus caeruleus) from near Rangpur, north-western Bangladesh.
U. Kuch
Identification: Usually 0.8-1.2 m (up to 1.75 m) long, hatchlings about
25 cm. Very narrow white bands on back of shiny black to dark brown
body and tail (often absent from anterior body). Belly uniformly light. Tail tip
pointed. Fifteen rows of scales across back, scales along vertebral ridge
much larger than bordering scales. Scales on lower side of tail undivided.
mountains of Nepal, known from <100-1525 m. Also eastern Afghanistan,
Pakistan, India, Sri Lanka, Bangladesh. Prefers forests, grasslands, agricultural
lands and residential areas; hides in houses, rodent burrows, crevices, piles of
bricks, rocks, rubble or woods.
Medical importance and behaviour: One of the most common and most
dangerous causes of snake bite envenoming in Nepal. Feeds on snakes,
rodents and other small animals. Active at night. Climbs and swims well.
Typically bites sleeping people inside their homes. Envenoming by this
species can cause death in a short time, but often several hours elapse
between bite and onset of paralysis. In most fatal cases death occurred
within 12-24 hours.
27
U. Kuch
Venom effects: Bungarus caeruleus venom causes abdominal pain
and progressive paralysis of the peripheral nervous system, leading
to respiratory paralysis and death due to asphyxia. Early signs include
abdominal pain, headache, convulsions; paralysis usually starts with the
eyelids and other muscles of the face. Early assisted ventilation and airway
management are crucial and life-saving.
Fig. 47. Juvenile Common Krait (Bungarus caeruleus)
from Pakistan, protecting itself by coiling up and hiding
its head under the body.
28
D. A. Warrell
U. Kuch
Fig. 46. Adult Common Krait (Bungarus caeruleus) from near Rangpur, north-western Bangladesh,
showing reduction of light bands on anterior body.
Fig. 48. Common Krait (Bungarus caeruleus)
from Pune, India. Top left part of the body
dilated after ingestion of a prey item.
Bungarus fasciatus
Banded Krait (English), Gangawari, Panhelo-kalo Chure Sarpa, Kanthamala,
Laxmi Sanp, Raja Sanp, Maher, Gwala Sarpa, Ahiriniya Sanp (Nepali)
U. Kuch
Identification: Usually 1-2 m (up to 2.25 m) long, hatchlings about
30-35 cm. Broad black and light rings of similar width on body and
tail. Light rings yellow in adults, cream to white in juveniles, extending
completely across belly. Tail tip blunt, not pointed, sometimes
mistaken for a second head. Body triangular, vertebral column
forming distinct ridge along top of the back. Fifteen rows of scales
across back, scales along vertebral ridge much larger than bordering
scales. Scales on lower side of tail undivided.
Fig. 49. Banded Krait (Bungarus fasciatus) from Damak, Jhapa, Nepal, trying to hide its head under
a leave as part of its typical defensive behaviour. During the day, these snakes are inactive and very
reluctant to bite.
mountains of Nepal. Elsewhere, from India east to China and south to
Indonesia. Known from coastal and mangrove swamps at sea level to
mountain forests at 2300 m altitude (in Myanmar). Prefers wet habitats
and vicinity of water (e.g., ponds, streams, rice fields, near villages).
Medical importance and behaviour: Common snake, active at night,
often seen by people. Its favourite food are snakes including venomous
ones. Usually hides head under body if disturbed, hissing and making jerking
movements. Bites appear to be rare in Nepal but envenoming by this species
is very dangerous and can result in death in a short time.
29
W. Grossmann
Venom effects: The major dangerous effect of B. fasciatus venom
is progressive paralysis of the peripheral nervous system, leading to
respiratory paralysis and death due to asphyxia. Systemic muscle damage
with myoglobinuria, acute renal failure and hyperkalaemia has caused
death in a case suspected to have been caused by this species in northwestern Bangladesh. Thus, both neurotoxic and myotoxic envenoming
and their complications should be anticipated.
U. Kuch
Fig. 50. Juvenile Banded Kraits (Bungarus fasciatus) have a pattern of white to cream and black rings on
the body. The white rings become yellow as the snakes grow.
Fig. 51. Close-up view of the tail tip of a Banded Krait (Bungarus fasciatus). The tail tip of adults of this
species is thicker and more rounded than in most other snakes.
30
U. Kuch
U. Kuch
Fig. 52. Ventral side of a Banded Krait (Bungarus fasciatus). The light and black bands encircle the body
completely, and they are of similar width.
Fig. 53. Adult Banded Krait (Bungarus fasciatus) displayed by a snake charmer in Bangladesh. Snake
charmers often handle Banded Kraits very carelessly because they know that these snakes rarely bite
at daytime. However, during the night when they are active, Banded Kraits readily defend themselves
by biting.
31
Bungarus lividus
Lesser Black Krait (English), Sano Kalo Karet (Nepali)
A
U. Kuch
Identification: Usually 60-90 cm long, rarely more than 1 m. Shiny black,
brownish black or brown head, body and tail with no light bands or
lines. Lower side of head and anterior body whitish, obscured by brown
pigment on lower side of posterior body and tail. Tail tip pointed. Fifteen
rows of scales across the back. Scales along vertebral ridge only slightly
larger than the bordering scales or of normal size. Scales on lower side
of tail undivided.
B
Fig. 54. (A) Lesser Black Krait (Bungarus lividus). Preserved museum specimen from near Dinajpur,
Bangladesh. In live snakes, the eye appears like a solid jet black bead and the pupil (white on the photo)
is difficult to see. (B) Same specimen, showing the pointed snout that may be used for digging in loose soil
or leaf litter, and the whitish lower side of the head and throat.
mountains of Nepal; so far known from central and eastern parts. Elsewhere,
north-eastern India and northern Bangladesh. Known from forests, grasslands,
agricultural lands and residential areas below 250 m altitude.
Medical importance and behaviour:
Very little is known about this rarely
encountered snake. It is active at night
and known to eat snakes and rodents
and to come into houses at night. There
have been few proven bites by this
species which is likely often confused
with B. caeruleus. Envenoming by
this species has caused death within
24 hours and may be common in
some areas.
32
A
B
Fig. 55. Strongly enlarged vertebral scales on the
back of Bungarus niger (and other kraits, A) and
only slightly enlarged vertebral scales of Bungarus
lividus (B). Drawing modified from F. Wall (1908)
U. Kuch
Venom effects: The venom of B. lividus has not been studied yet.
Envenoming by this species in Nepal has caused burning sensation at
the bite site and over the whole body, abdominal pain, vomiting, slurred
speech, ptosis, and progressive generalized neuromuscular paralysis
leading to respiratory distress and death. Neurotoxic and possibly myotoxic
envenoming and their complications should be anticipated when treating
a patient bitten by this snake.
U. Kuch
Fig. 56. Adult male Lesser Black Krait (Bungarus lividus).
This snake caused a fatal bite inside the Beldangi Refugee
Camp of Jhapa District, Nepal, where it had hidden under
a pillow in a bed. It was subsequently killed by neighbours.
Fig. 57. Lesser Black Krait (Bungarus lividus). Ventral side
of the same snake showing the light anterior part of the belly
that is gradually obscured with dark pigment on the posterior
body.
33
Bungarus niger
Greater Black Krait (English), Thulo Kalo Karet (Nepali)
F. Tillack
Identification: Usually 70-90 cm long, rarely up to 1.3 m. Shiny black,
brownish black or dark chocolate brown head, body and tail with no light
bands or lines. Lower side of head and anterior body dirty white to yellow,
obscured by brown pigment on lower side of posterior body and tail. Tail tip
pointed. Fifteen rows of scales across the back, scales along vertebral ridge
much larger than the bordering scales. Scales on lower side of tail undivided.
Fig. 58. Greater Black Krait (Bungarus niger) viewed from above. Note the greatly enlarged row of scales
running along the middle of the back, the key feature to distinguish this species from the other black krait
in Nepal, Bungarus lividus.
Distribution and habitat: Lowlands and lower mountains probably
throughout Nepal, but so far recorded only from Kaski District at 1450 m
altitude. Elsewhere, found from mangrove swamps at sea level to mountain
forests, agricultural lands and residential areas from north-western India
(Uttarakhand) to Bhutan, north-eastern India, Bangladesh and western
Myanmar.
34
Medical importance and behaviour: The fact that B. niger is a medically
important snake was only discovered in recent years. It is active at night
and known to come into houses or become entangled in fishing nets,
and to eat rodents and snakes. Bites by this species have often been
confused with B. caeruleus bites. They can cause death within 24 hours.
F. Tillack
Venom effects: The venom of B. niger causes progressive paralysis of the
peripheral nervous system, leading to respiratory paralysis and death due
to asphyxia, and it causes systemic muscle damage with myoglobinuria,
acute renal failure and hyperkalaemia. Thus, the complications of both
neurotoxic and myotoxic envenoming must be anticipated in patients
bitten by such a snake. Assisted ventilation is crucial and dialysis may be
needed, too.
Fig. 59. Greater Black Krait (Bungarus niger) from Naudanda, Kaski, Gandaki, Nepal, 1450 m altitude.
Detailed view of the head of the same snake. Note the very small eye that appears jet black without
visible pupil.
35
Bungarus walli
Wall's Krait (English), Bairi Karet, Gadaich (Nepali)
Fig. 60. Wall’s Krait (Bungarus walli), specimen from Lakshmipur District, Bangladesh.
M.A.W. Chowdhury
Identification: Usually 1-1.3 m long (up to 1.65 m), hatchlings about
25-30 cm. Shiny black, brownish black or grey head, body and tail with
numerous very narrow white or yellowish bands. Light bands often much
obscured on anterior body and less than one scale wide. Belly uniformly
white. Tail tip pointed. Seventeen (rarely 19 or 21) rows of scales across the
back; scales along vertebral ridge much larger than the bordering scales. Scales
on lower side of tail undivided.
Distribution and habitat: Likely throughout the lowlands of Nepal but
so far known from the southeast only. Elsewhere, from the Gangetic
floodplains of northern India to the delta region of Bangladesh. Known
from grasslands, open forests, agricultural lands and residential areas.
Medical importance and behaviour: Bungarus walli was only recently
identified as a medically important snake because it had usually been
mistaken for B. caeruleus. In certain areas both species occur but in others
one of the two is the leading cause of krait bite envenoming. Envenoming
36
by B. walli appears to be common in south-eastern Nepal. Active at night;
known to feed on rodents, snakes and frogs. Highly dangerous; apparently
more irritable than B. caeruleus.
A
M.A.W. Chowdhury
Venom effects: The venom of B. walli has not been studied so far.
Envenoming by this species has caused a clinical syndrome similar to
that of B. caeruleus envenoming. In addition to progressive paralysis of
the peripheral nervous system leading to respiratory paralysis, however,
individual patients also had convulsions, cardiac complications and
variable degrees of haemo/myoglobinuria.
B
Fig. 62. Wall’s Krait (Bungarus
walli, A) and Common Krait
(Bungarus caeruleus, B).
Although the two species look
similar, they can be reliably
distinguished by the number
of scale rows across their
back: Bungarus caeruleus has
only 15, but Bungarus walli 17
(rarely 19-21).
A
B
U. Kuch
Fig. 61. (A) Wall’s Krait (Bungarus walli) from Lakshmipur, southern Bangladesh, showing details of the
head pattern. In Common Kraits (Bungarus caeruleus) the distinction between the dark and light areas on
the head is often less clear. (B) Same specimen showing details of the narrow white bands and greatly
enlarged row of scales along the middle of the back.
37
Naja naja
Common Cobra, Spectacled Cobra (English), Goman, Nag (Nepali)
U. Kuch
Identification: Usually 1.5-1.6 m
(up to 2.2 m) long, hatchlings about
25-30 cm. Light brown, tan to black
ground colour with spectacleshaped mark on neck, two black
spots on lower side of throat and 2
or 3 broad black cross-bars on the
belly behind the hood. Twenty-one
to 25 rows of scales across back
at midbody; scales along vertebral
ridge of same size as bordering
scales. Tail tip pointed; scales on
lower side of tail divided.
Fig. 63. Spectacled Cobra (Naja naja) showing
its defensive display with vertically raised anterior
body and spread "hood".
Distribution and habitat: Likely
throughout the lowlands and lower
mountains of Nepal up to at least
1600 m altitude. Elsewhere, Pakistan,
India, Sri Lanka, Bhutan, Bangladesh;
in forests, grasslands, agricultural
lands, and residential areas.
Medical importance and behaviour: One of the most common and
most dangerous causes of snake bite envenoming in Nepal. Active by day
and night, especially at dawn and dusk. Feeds mainly on rodents, frogs,
birds; swims well. Raises forebody, displays extended neck skin "hood"
and hisses when disturbed.
Venom effects: Envenoming by N. naja causes local swelling of the
bitten part and in a large number of cases also progressive paralysis
of the peripheral nervous system, leading to respiratory paralysis and
death due to asphyxia. Neurotoxic features of N. naja envenoming are
typically reversible by antivenom and anticholinesterase treatment. Local
envenoming may result in tissue necrosis and contractures requiring
surgical intervention.
38
U. Kuch
U. Kuch
Fig. 64. Spectacled Cobra (Naja naja) showing its defensive display with "spectacle-shaped" marks on the
back of its neck skin while trying to escape.
Fig. 65. Spectacled Cobra (Naja naja) from Damak, Jhapa District, Nepal. The ground colour of cobras
is quite variable and may range from light brown to almost black. The specimen on this photo appears
especially dark because it will soon shed the old upper layer of its skin.
39
Naja kaouthia
K.B. Shah
Monocellate Cobra, Monocled Cobra (English), Goman, Paniyadarad (Nepali)
(up to 2.3 m) long, hatchlings about
25-35 cm. Light brown, tan to black
ground colour with monocellate
(O-shaped) mark on neck, two
black spots on lower side of throat
and 2 or 3 broad black crossbars on the belly behind the hood.
Twenty-one (sometimes 19-23)
rows of scales across the back at
midbody; scales along vertebral
ridge of same size as bordering
scales. Tail tip pointed; scales on
Distribution and habitat: Likely
throughout the lowlands and
Fig. 66. Monocellate Cobra (Naja kaouthia) from
lower mountains of central and
Bara District, Nepal.
eastern Nepal up to at least
3200 m. Elsewhere, Bhutan, north-eastern India, Bangladesh and
Myanmar to China, Vietnam and north-western Malaysia. Prefers forests,
grasslands, agricultural lands and residential areas close to water.
Medical importance and behaviour: Bites by this species appear to
be less common than those by N. naja in Nepal although in most cases
of cobra bite the species involved is not identified. Active by day and
night, especially at dawn and dusk. Feeds mainly on frogs, toads, fish and
rodents; swims well. Raises forebody, displays extended neck skin "hood"
and hisses when disturbed.
Venom effects: Envenoming by N. kaouthia causes local swelling of the
bitten part and in a large number of cases also progressive paralysis of
the peripheral nervous system, leading to respiratory paralysis and death
due to asphyxia. Neurotoxic features of N. kaouthia envenoming are typically
reversible by antivenom and anticholinesterase treatment. Local envenoming
may result in tissue necrosis and contractures requiring surgical intervention.
40
U. Kuch
Fig. 68. Monocellate Cobra (Naja kaouthia) showing the characteristic neck mark in defensive display.
41
U. Kuch
Fig. 67. Monocellate Cobra (Naja kaouthia) in a snake charmer’s collection in Bangladesh.
Ophiophagus hannah
King Cobra (English), Raj Goman, Kalinag, Kenwata (Nepali)
Identification: Usually 3-3.5 m (up to 5.5 m) long, hatchlings about
40-60 cm. It is the largest venomous snake in the world. Shiny black to
brown, grey or tan ground colour. Juveniles with distinct narrow white or
yellowish bands on body and tail, faded and indistinct in most adults. Back
of the neck without spectacle-shaped or monocle-shaped spots. A pair of
large occipital shields in contact with one another on top of the head. Tail
tip pointed. Fifteen rows of scales across back at midbody, scales along
vertebral ridge not larger than bordering scales. Scales on lower side of tail
undivided anteriorly and divided posteriorly.
mountains of Nepal up to 3500 m altitude. Also India, Bangladesh, Bhutan
and Southeast Asia. Prefers forests and plantations in the vicinity of water
and bamboo stands; rarely seen in disturbed agricultural lands.
Venom effects: Envenoming
by O. hannah causes local
swelling of the bitten part
and progressive paralysis
of the peripheral nervous
system, leading to respiratory
paralysis and death due to
asphyxia. As king cobras
can inject huge amounts of
a venom that is not included
Fig. 69. King Cobra (O. hannah) from Kathmandu, Nepal.
in the production of Indian
polyvalent antivenoms, large amounts of antivenom may be needed
for neutralization. Local envenoming may result in necrosis requiring
surgical intervention.
42
K.B. Shah
Medical importance and behaviour: King cobras are active by day,
move rapidly, climb and swim well. They mainly feed on snakes including
pythons, sometime also on other reptiles like monitor lizards. When
cornered they raise their anterior body and emit a deep growling sound.
Bites appear to be rare in Nepal.
A. Captain/Indian Herp. Society
Fig. 70. King Cobra (Ophiophagus hannah) from Orissa, India.
43
Sinomicrurus macclellandi univirgatus
MacClelland´s Coral Snake (English), Mugasanp, Karkat Nag (Nepali)
A. Captain/The Lisus
Identification: Usually 50-80 cm long. Head black above with a wide
white, yellow or cream coloured transverse stripe behind the eyes. Back of
the body reddish brown with or without a black vertebral stripe or remains
of incomplete thin black transverse bands on the flanks; below yellowish
with black bars or quadrangular spots. Thirteen rows of scales across the
back; scales along vertebral ridge not larger than bordering scales. Tail short
with pointed tip. Scales on lower side of tail divided (rarely some undivided).
Fig. 71. MacClelland's Coral Snake (Sinomicrurus macclellandi). Adult specimen from Arunachal
Pradesh, India.
Distribution and habitat: Lowlands and lower mountains from western, central
to eastern Nepal up to at least 2200 m. Also reported from north-eastern
India (Sikkim). Known from forests, scrublands and agricultural lands.
Medical importance and behaviour: Very little is known about this
rare snake. It appears to be active at night, dawn and dusk, digs well in
loose soils and is reported to feed on earthworms, snakes and beetles. If
cornered, it responds by flattening its body and lifting and curling its tail.
Bites appear to be very rare in Nepal but one fatal case was reported.
44
A. Captain/The Lisus
Venom effects: The venom of this species has not been studied so
far. The available information suggests that it causes severe neurotoxic
envenoming leading to respiratory paralysis. However, as several other
coral snake venoms are known to also have myotoxic activities, both
neurotoxic and myotoxic envenoming and their complications should be
anticipated when treating a patient bitten by this snake.
K.B. Shah
Fig. 72. MacClelland's Coral Snake (Sinomicrurus macclellandi) from Arunachal Pradesh, India. Note
the broad white cross-band behind the eyes.
Fig. 73. MacClelland's Coral Snake (Sinomicrurus macclellandi univirgatus) from Ilam District, Nepal.
45
H.H. Schleich
H.H. Schleich
Fig. 74. MacClelland's Coral Snake (Sinomicrurus macclellandi univirgatus) from the Kathmandu Valley,
Nepal. The snake uses its raised and flattened tail in defense to distract the enemy's attention from its head.
Fig. 75. MacClelland's Coral Snake (Sinomicrurus macclellandi univirgatus) from the Kathmandu
Valley, Nepal. In this subspecies the black pattern on the back is reduced to a stripe or series of spots
along the back.
46
Vipers and pit vipers (family Viperidae)
This group comprising species like Russell's Viper, the Mountain Pit Viper,
and all green pit vipers is characterized by having two very long fangs
that are also attached to the upper front of the jaw in the mouth but are
mobile and can be folded back when not in use. These fangs are erected
only when the snake opens its mouth and attempts to bite (see Fig. 3).
This option of folding back the fangs has allowed this group of snakes to
penetrate fur, feathers, or thick skin of the prey - and clothes or certain
shoes of human snake bite victims. In the processes of evolution, these
long fangs have reached a level of perfection that is superior to that of
any other snake tooth: They are hollow like a medical injection needle,
and they work just like this.
F. Tillack
The venom of these snakes is very different from that of cobras, king cobras,
kraits and coral snakes. One particular feature of the venom of vipers and
pit vipers is that it causes pain very soon after the bite – much more pain
than the bite itself. However, the degree of pain caused by these venoms
is not predictive of the real medical complications they cause. In fact, many
cases especially of pit viper bites only result in painful local swelling without
serious complications, and this swelling usually subsides after a few days.
In some cases, there will be more serious venom effects like changes in
blood coagulation abilities, bleeding from body parts other than the bite
site, local destruction of tissues or kidney problems. This is why all of these
bite accidents should be observed in hospital so that complications can be
prevented or treated immediately.
Fig. 76. Kramer's Pit Viper
(Trimeresurus septentrionalis),
adult female from Pyaudi,
Kaski, Gandaki, Nepal, 1050 m
above sea level.
47
Daboia russelii
Russell's Viper (English), Baghesarpa, Suskar (Nepali)
D. A. Warrell
Identification: Usually 0.9-1.5 m (up to 1.8 m) long, hatchlings about
24 cm. Light brown ground colour with three longitudinal series of large
rounded or oval spots on the
body. The centre of each spot
is usually brown bordered with
black and yellow or white edges.
Occasionally, these spots touch
each other or fuse. Two large
symmetrical dark brown marks
on top of the head. Top of
head covered by many small
and strongly keeled scales. At
midbody, 27-33 rows of scales
across the back, all except outer
rows strongly keeled. Scales on
Fig. 77. Russell's Viper (Daboia russelii), adult
specimen from Pune, Maharashtra, India.
Distribution and habitat: In Nepal known from very few localities in the
lowlands only (<100-250 m altitude). Also India, Pakistan, Bangladesh,
Bhutan, Sri Lanka from sea level up to 2756 m. Prefers open grassy
areas, scrublands, forest edges, agricultural lands (often rice fields) and
residential areas.
Medical importance and behaviour: Elsewhere one of the medically
most important highly dangerous snake species. No confirmed bites
by Russell’s Viper are known from Nepal yet. Ambush predator feeding
on rodents, birds, lizards and frogs. Usually inactive at day but active at
night, dawn and dusk; produces very loud and deep hissing sound when
disturbed and vigorously strikes in defence.
Venom effects: Envenoming by D. russelii causes painful local swelling,
non-clotting blood, internal and external bleeding and cardiovascular
shock; in some areas additionally myotoxicity with myoglobinuria and
renal failure or neurotoxicity with paralysis. Local envenoming may result
in massive loss of body fluids into tissues, and in blistering and necrosis
requiring surgical intervention.
48
D.A. Warrell
A. Captain/S. Thakur/Indian Herp. Society
Fig. 78. Russell's Viper (Daboia russelii), adult specimen from Pune, Maharashtra, India.
Fig. 79. Juvenile Russell's Viper (Daboia russelii) from Maharashtra, India.
49
Gloydius himalayanus
Himalayan Pit Viper (English), Bhyagute Sarpa (Nepali)
F. Tillack
Identification: A small viper
with pit organ between
nostril and eye. Usually 4060 cm (up to 86 cm) long;
hatchlings about 16-20 cm.
The large triangular head
is very distinct from the
neck. The top of the head
is covered with large scales
Fig. 80. Himalayan Pit Viper (Gloydius himalayanus), adult
in the front and small scales
male from Kalopani, Mustang District, Nepal, 2500 m.
in the back. A black stripe
extends from the eye to the corner of the mouth. Body colour brown
or grey with dark brown or blackish brown spots, zig-zag bands or
horse-shoe shaped blotches; lower side of the body brown speckled with
black and white. Body scales strongly keeled, arranged in 21 (rarely 23)
rows at midbody. This species is also known as Agkistrodon himalayanus
in the older literature.
Distribution and habitat: Hills and mountains of Nepal from 1640-3060 m
altitude; also in north-western India, Pakistan (up to 4880 m) and possibly
eastern Afghanistan. Prefers dry coniferous forests, subalpine scrublands,
alpine meadows and agricultural lands.
Medical importance and behaviour: Clinical data on envenoming by
this species are lacking but it is considered to be of lesser medical concern
in Nepal. It may be active mostly at day and is thought to mainly feed on
rodents and lizards.
Venom effects: The venom of this species and its effects have not been
studied so far. Envenoming by other species of Gloydius usually cause
painful local swelling, non-clotting blood, and more rarely bleeding and/or
blistering and necrosis at the bite site.
50
F. Tillack
F. Tillack
Fig. 81. Himalayan Pit Viper (Gloydius himalayanus), adult female from
Syang, Mustang District, Nepal, 2700 m altitude.
F. Tillack
Fig. 82. Himalayan Pit Viper (Gloydius himalayanus), adult female from
Syang, Mustang District, Nepal, 2700 m altitude.
Fig. 83. Himalayan Pit Viper (Gloydius himalayanus), juvenile with striped
pattern from Mustang District, Nepal.
51
Himalayophis tibetanus
Tibetan Pit Viper, Karan´s Pit Viper, Shah´s Pit Viper (English), Haryou
Sarpa, Pattar, Karanko Haryou Sap (Nepali)
F. Tillack
Identification: A medium sized viper with pit organ between nostril
and eye. Usually 40-70 cm long; hatchlings about 15-20 cm. The large
triangular head is very distinct from the neck. The top of the head is
covered with small scales. The colour pattern of the body is highly variable.
It varies from grass green to yellowish-olive or reddish-brown with irregular
reddish-brown pattern or scattered short brown bands along the back.
The tail is green with red to brown spots; the belly light green yellowish or
light brown, patternless or with dark mottling. Young snakes have a light
greyish or brownish ground colour with a dark brown or black pattern
along the back and sides. The upper body scales are keeled and arranged
in 19-21 rows at midbody. This species was previously also known under
the scientific names Trimeresurus karanshahi and Trimeresurus tibetanus.
Fig. 84. Tibetan Pit Viper (Himalayophis tibetanus), adult male from Phulchoki, Godavari, Lalitpur
District, Nepal, 2525 m altitude.
52
Distribution and habitat: The identity and distribution of this species
was poorly known until recently. This is also why it was known under
different names in the scientific literature. This is a mountain species that
has been found in central Nepal at Phulchoki mountain and Helambu area
of Sindhupalchok District from 2500-2700 m altitude; also in neighbouring
areas of China (Tibet) up to 3200 m. It prefers oak and rhododendron
forests and bush thickets and large rocky grass slopes.
Medical importance and behaviour: Clinical data on envenoming by
this species are lacking but it is so far considered to be of lesser medical
concern. It may be active at day and night and probably feeds on rodents.
Fig. 85. Tibetan Pit Viper (Himalayophis tibetanus), adult female from Phulchoki, Godavari, Lalitpur
F. Tillack
studied so far. Envenoming by other green pit vipers usually causes
painful local swelling, non-clotting blood, and more rarely bleeding and/or
blistering and necrosis at the bite site.
53
Fig. 87. Tibetan Pit Viper (Himalayophis tibetanus), adult female of the brown variety, Tark Ghyang,
Helambu, Bagmati, Nepal, 2560 m above sea level.
54
F. Tillack
Fig. 86. Tibetan Pit Viper (Himalayophis tibetanus), adult female from Phulchoki Mountain, Godavari,
Bagmati, Nepal, 2670 m above sea level.
F. Tillack
F. Tillack
Fig. 89. Tibetan Pit Viper (Himalayophis tibetanus), recently hatched juvenile from Helambu, Sindhupalchok
District, Nepal.
F. Tillack
Fig. 88. Tibetan Pit Viper (Himalayophis tibetanus), subadult female from Melamchigaon, Helambu,
Sindhupalchok District, Nepal, 2590 m altitude.
55
Ovophis monticola
Mountain Pit Viper (English), Andho Sarpa, Gurube, Chhirbire Sarpa (Nepali)
F. Tillack
(up to 1.3 m) long, hatchlings
about 16-21 cm. Head triangular
in shape and very distinct from the
neck. Pit organ present between
nostril and eye. Numerous small
and smooth scales on top of
the head; top and sides of the
Fig. 90. Mountain Pit Viper (Ovophis monticola),
head dark brown. Upper side
subadult specimen from Naudanda, Kaski
of body light or dark brown with
a series of large rectangular
blotches and irregularly distributed dark brown or yellowish brown
spots; body sides with smaller dark brown blotches. Body scales
smooth or weakly keeled; arranged in 23-25 (rarely 21 or 26) rows
at midbody.
Distribution and habitat: In Nepal wide-ranging in the hills and mountains
from 900-2680 m altitude. Also in India, Bhutan, Myanmar, China and
Southeast Asia. Found in oak, rhododendron and coniferous forests,
grasslands, often in agricultural lands, and in and around houses.
Medical importance and behaviour: One of the most widely distributed
and frequently encountered venomous snake species of Nepal and
probably the medically most important snake species of the highlands.
Ambush predator feeding on rodents, frogs, lizards and birds. Usually
active at night, dawn and dusk. Sluggish but highly aggressive when
disturbed. Although mild local envenoming seems to be most common,
bites by juveniles have caused severe prolonged bleeding, and long-term
sequelae and fatalities have been recorded.
Venom effects: Envenoming by O. monticola can cause painful local
swelling, non-clotting blood, internal and external bleeding and related
complications. Local envenoming may result in massive loss of body fluids
into tissues, and in blistering and necrosis requiring surgical intervention.
56
F. Tillack
F. Tillack
Fig. 91. Mountain Pit Viper (Ovophis monticola), close-up view of the head of an adult female from Kaski
District, Nepal.
Fig. 92. Mountain Pit Viper (Ovophis monticola), female with eggs from between Naudanda and Tulakhet,
Kaski District, Nepal.
57
Fig. 94. Mountain Pit Viper (Ovophis monticola), juvenile specimen, near Naudanda, Kaski District, Nepal.
58
F. Tillack
Fig. 93. Mountain Pit Viper (Ovophis monticola), one year old specimen from Kaski District, Nepal.
F. Tillack
Protobothrops sp.
Himalayan Habu Pit Viper (English)
F. Tillack
Identification: A large viper with pit organ between nostril and eye
and a lance-shaped head that is very distinct from the neck. Usually
1.1-1.4 m long. Upper body yellowish-olive or olive brown, with a series
of 42-50 irregularly shaped reddish brown bands (sometimes broken at
the sides) with black and yellow borders. Head dark reddish-brown above
without pattern, amber or yellowish at the sides below the eye. Belly cream
or yellowish-grey with numerous dark brown spots in chessboard-like
pattern. Scales on top of the head small and smooth. Body scales strongly
keeled (except outer 2-3 rows) and arranged in 24-25 rows at midbody.
Fig. 95. Himalayan Habu Pit Viper (Protobothrops sp.) from Dolakha District, Nepal, 2600 m altitude, viewed
from above. Preserved museum specimen courtesy of California Academy of Sciences (CAS 90668).
Distribution and habitat: The identity and distribution of this species is
poorly known in Nepal where it has so far only been found in Simigaon,
Dolakha District at 2600 m altitude. Similar species of Protobothrops pit
vipers inhabit forests, scrublands and the banks of small streams in the
mountains of northeastern India, Bhutan, Myanmar, China, and northern
Southeast Asia.
59
Medical importance and behaviour: No proven bites by this species
have been recorded in Nepal. However, envenoming by these snakes has
to be regarded as potentially extremely dangerous due to their large size
and venom quantity.
F. Tillack
A
B
Fig. 96. Himalayan Habu Pit Viper (Protobothrops sp.) from Dolakha District, Nepal (CAS 90668). Note
the numerous small scales on top of the head (A). Head of the same specimen viewed from the side (B).
F. Tillack
Venom effects: Envenoming by other species of Protobothrops pit vipers
has caused painful local swelling, non-clotting blood, internal and external
bleeding and cardiovascular shock, myotoxicity with myoglobinuria and
renal failure. Local envenoming may result in massive loss of body fluids
into tissues, and in blistering and necrosis requiring surgical intervention.
Fig. 97. Himalayan Habu Pit Viper (Protobothrops sp.), same specimen (CAS 90668) viewed from below.
60
Trimeresurus cf. albolabris
White-lipped Pit Viper (English), Haryou Sarpa, Pattar (Nepali)
Identification: A medium-sized viper with pit organ between nostril and
eye. Usually 50-70 cm, rarely up to 1 m long, juveniles about 12-18 cm.
The large triangular head is very distinct from the neck. The top of the head
is covered with many small and smooth scales. Body colour bright green,
eye amber or yellow, edges of lip scales bordering the mouth often white.
Tail above with continuous reddish-brown colour, belly yellowish-white.
Body scales keeled, arranged in 21 rows (rarely 19 or 23) at midbody.
Distribution and habitat: Found throughout the southern lowlands, hills
and low mountains. Together with Ovophis monticola the most commonly
encountered pit viper of Nepal. Elsewhere in the lower elevations of
the eastern Himalayas (India and Bhutan). Inhabits open subtropical
and tropical forests, grasslands, agricultural lands and residential areas
surrounded by vegetation; mostly lives in trees, shrubs and small bushes.
Medical importance and behaviour: Although proven cases of
envenoming by this species are rare, it is believed to be one of the most
common causes of snake bite in low and intermediate elevations of Nepal.
Frequently found active on the ground especially at night, hunting rodents,
frogs, lizards and small birds and occasionally entering houses. Usually
a gentle snake relying on its camouflage but defending itself quickly with
bites when touched or approached closely.
Venom effects: Envenoming by this and other closely related pit viper
species usually causes painful local swelling, non-clotting blood, and rarely
systemic bleeding and/or blistering and necrosis at the bite site. Serious
complications and fatalities are rare.
Note: Several species of "green pit vipers" that look very similar to this
species and T. septentrionalis have been reported in the Himalayan region
(e.g. gramineus, erythrurus and yunnanensis). In most cases, their real
identity and occurrence in the region is insufficiently documented and
records from Nepal have so far proved unfounded.
61
A. Gumprecht, specimen courtesy of Fuhlrott Museum
Fig. 98. White-lipped Pit Viper (Trimeresurus cf. albolabris). Adult snake from southern Nepal.
62
Trimeresurus septentrionalis
Kramer’s Pit Viper (English), Haryou Sarpa, Pattar (Nepali)
Distribution
and
habitat:
Common in the mid-hill regions of
Nepal (Myagdi, Kaski, Lamjung,
Rasuwa) where it inhabits scrublands,
bamboo thickets, agricultural lands
and forests from 900-3050 m altitude.
Outside Nepal reliable records of
this species are only known from
north-western India (Uttarakhand).
F. Tillack
F. Tillack
Identification: A medium sized
viper with pit organ between
nostril and eye. Usually 50-75 cm
long, juveniles about 15-20 cm.
The large triangular head is
very distinct from the neck. The
top of the head is covered with
many small and smooth scales.
Fig. 99. Kramer's Pit Viper (Trimeresurus septentrionalis),
adult female from Dhikur Pokhari, Kaski District, Nepal,
Body colour dark green, head
1500 m altitude.
below the eye light green or
yellowish, eye yellow. Tail above bright red, belly light yellowish-green.
Body scales keeled, arranged in 21 rows at midbody. This species is also
known as Trimeresurus albolabris septentrionalis in the older literature.
Fig. 100. Kramer's Pit Viper (T. septentrionalis),
adult female from Pyaudi, Kaski District, Nepal,
1050 m altitude.
Medical importance and behaviour: Clinical data on proven cases of
envenoming by this species are rare but it is believed to be a common
cause of snake bite where it occurs in Nepal. Mostly active at night and
thought to mainly feed on rodents and frogs.
studied so far. Envenoming by other closely related "green pit vipers”
usually causes painful local swelling, non-clotting blood, and more rarely
bleeding and/or blistering and necrosis at the bite site. Such clinical
conditions have also been observed in patients from areas in Nepal where
T. septentrionalis is known to occur.
63
F. Tillack
F. Tillack
Fig. 101. Kramer's Pit Viper (Trimeresurus septentrionalis), adult female from Pyaudi, Kaski, Gandaki, Nepal,
1050 m altitude. Note the small scales on top of the head and the pit organ between the eye and the nostril.
Fig. 102. Kramer's Pit Viper (Trimeresurus septentrionalis), adult female from Pyaudi, Kaski, Gandaki,
Nepal, 1050 m altitude. Note the reddish-brown colour on the back of the tail.
64
Other venomous snakes
F. Tillack
In addition to the members of these two groups, one species of snake
among the many that have enlarged teeth only in the rear of the mouth is
also included here, the Red-necked Keelback (Rhabdophis subminiatus).
Numerous species of snake with such a "rear-fanged" type of dentition
occur in Nepal, and they are generally regarded as harmless or only
mildly venomous. However, this particular one is known to have caused
serious envenoming in humans. All of the few known bites by this species
happened in other countries, and in people who handled the snakes on
purpose. Often, the bitten persons even let these snakes chew on the
bite site for several minutes, unknowingly allowing them to inject larger
amounts of their toxic oral gland secretion into the wound. In the context
of Nepal, no case of envenoming by this species or any other rear-fanged
snake has been reported. Still, the Red-necked Keelback is included in
this book because its bite can cause life-threatening envenoming. Its case
should serve as a warning to treat all snakes with respect, not to play with
snakes (and not to let children play with them), and to seek medical advice
if unusual things happen after the bite by any snake.
Fig. 103. Red-necked Keelback (Rhabdophis subminiatus). Adult female from Khao Lak, Phang Nga,
Thailand.
65
Rhabdophis subminiatus
Red-necked Keelback (English)
Fig. 104. Red-necked Keelback (Rhabdophis subminiatus) from Khao Lak, Phang Nga, Thailand.
F. Tillack
Identification: Usually 75-95 cm (up to 1.3 m) long, hatchlings about 13-19
cm. Head, body and tail with olive, light brown or greenish tan ground colour.
Back of the neck with orange to red colour. Distinct oblique black bar below
the eye. Scales across the back arranged in 19 rows at midbody, all but those
of the outer rows strongly keeled.
Distribution and habitat: So far recorded from Chitwan District (200 m
altitude) only but likely to occur throughout the lowlands of Nepal. Also
from north-eastern India and Bangladesh east to China and south to
Indonesia. Prefers wet habitats and vicinity of water (e.g., ponds, streams,
rice fields, swamps).
Medical importance and behaviour: Rhabdophis subminiatus belongs
to the large and mostly non-dangerous group of freshwater snakes. It
66
is active at day, feeds on frogs and fishes, and has enlarged teeth
approximately at the level of the eyes that enable it to inoculate highly
active venom. When cornered, these snakes raise their head and neck,
presenting a narrow "hood" with red colouration. They readily bite to
defend themselves. This species has the potential to kill humans. The
longer the snake is allowed to chew on the bite site, the higher the risk that
significant envenoming will follow. There have been no confirmed bites by
R. subminiatus in Nepal but cases of life-threatening envenoming have
occurred in other countries.
F. Tillack
Venom effects: Envenoming by this species has caused headache,
nausea, vomiting, thrombocytopenia, erythrocyte fragmentation, and
profuse internal and external bleeding with non-clotting blood over weeks.
Rhabdophis subminiatus venom may be neutralized by Rhabdophis
tigrinus antivenom made in Japan.
Fig. 105. Red-necked Keelback (Rhabdophis subminiatus). Although it does not belong to the
front-fanged venomous snakes, bites by this species can cause life-threatening bleeding.
67
Management of Snake Bite
Introduction
• Snake bite is one of the most neglected public health problems in poor
rural communities in subtropical and tropical countries.
• It is an important occupational injury affecting farmers, plantation
workers, herders, and fishermen.
• South Asia is the most affected region in the world.
• In southern Nepal, up to 162 persons per 100,000 people die from
snake bite every year in certain regions of the country.
Clinical Features of Snake Bite
• The majority of snake bites are caused by non-venomous species.
• Even highly venomous snakes often bite without injecting any venom.
• Fear, particularly the fear of death, may produce symptoms that can
mimic systemic envenoming.
• Use of a tourniquet may lead to a swollen and damaged limb even in
the absence of envenoming.
• Clinical features of envenoming depend on the species of snake,
the quantity of venom injected and the composition of the venom.
Envenoming by juvenile and adult snakes of certain species can also
cause different clinical features.
• Cobra and Krait Bites
Ø Krait bites usually occur at night on sleeping people (often, but not
only on those sleeping on the ground) and may go unnoticed, so
that early morning pain in the abdomen with features of paralysis of
the eye muscles (difficulty to open the eyes) require urgent care.
Ø
Cobra bites usually occur in the daytime in Nepal, especially at dawn
and dusk.
68
Ø Envenoming due to cobra and krait bites manifests itself predominantly
with neuromuscular paralysis (neurotoxicity):
- Ptosis – inability to open the eyes on looking up
- Inability to open the mouth
- Inability to protrude the tongue from the mouth
- Inability to swallow
- Paralysis of the muscles of the hands and feet
- Difficulty in breathing
Ø Choking and inability to breathe may also result from the pooling of
secretions from the mouth, aspiration of vomitus, or blocked airway
by a paralyzed tongue.
ØLocal swelling, local infection, abscess formation and local tissue
damage (necrosis) is one of the important features of cobra
envenoming.
• Viper Bites
Ø The most common serious complication of viper bite envenoming is
bleeding.
ØBleeding from gingival sulci is usually the earliest sign of systemic
envenoming.
ØOther common sites of bleeding are partially healed wounds or
venepuncture sites.
ØIn severe envenoming, bleeding from any site is possible.
Ecchymoses (bleeding under the skin), subconjunctival bleeding (in
the eye), intraperitoneal haemorrhage (bleeding inside the abdomen),
subarachnoid and intracranial hemorrhages (bleeding inside the skull
and into the brain) may occur.
ØLocal complications at the bite site are common and may include
swelling, blisters, necrosis of the skin, soft tissues, connective tissues
and muscles.
69
First Aid
• Any person who happens to be nearby at the time of a snake bite, or
the victim himself, should carry out first aid.
• Reassure the victim; most are terrified and apprehensive.
• Immobilization of the bitten limb is an important and effective first aid
measure. Allow the victim to lay down in a comfortable and safe position.
• Immobilize the bitten limb with a splint or sling.
• Immediately transport the victim to the nearest health centre where
antivenom (anti-snake venom serum) is available. This is the most
important first aid measure. Transport by motorcycle or other motor
vehicles is key to save time.
Management at the Health Centre
• If the victim has no sign of envenoming, admit the patient and observe
for 24 hours. If signs of systemic or severe local envenoming are
present on admission or develop later, treatment with antivenom
and other supportive care is the key to the survival and cure of
the patient.
• Early assisted ventilation (manually by Ambu bag or mechanically) is
crucial to treat patients with respiratory paralysis. It may be required for
days or weeks but full recovery is possible if adequate oxygen levels
were maintained.
• Immediate Management
1. Assess vital signs, resuscitate if necessary and insert an intravenous line.
2.Evaluate for the presence of features of local envenoming.
3.Look for signs of neuromuscular paralysis or bleeding (other than
from the bite site).
4.Certain clinical situations demand urgent resuscitation, e.g.,
presence of profound hypotension and shock or respiratory failure.
5. Pay careful attention to the pre-admission history, closely observe the
patient and be prepared for rapid development of severe systemic
envenoming and sudden deterioration.
70
6.Snake bite envenoming, especially by kraits, can produce clinical
features that resemble brain death, like fixed dilated pupils and
invisible spontaneous respiration. These patients are paralysed and
can fully recover if adequately ventilated (manually or mechanically).
• Indications for Antivenom Injection
1.Signs of neuromuscular paralysis (drooping of eyelids, inability to
open the mouth or other signs described above).
2.Spontaneous bleeding.
3. In proven cases of Russell’s Viper bite: incoagulable (non-clotting) blood.
• Dose of Antivenom
ØSnakes inject the same dose of venom into children and adults.
Children must therefore be given exactly the same dose of antivenom
as adults.
ØPatients with signs of systemic envenoming should be treated with
antivenoms (also known as anti-snake venom serum) according to the
local protocol.
Prevention of Snake Bite
Many snake bites could be prevented by simple measures that aim to
reduce the likelihood of human-snake encounters, and to reduce the
chances of being bitten when meeting a snake.
• Keep it clean around the house and playground without bushes, stones,
mud, and piles of leaves.
• Keep everything away from the house (or in sealed containers) that
could attract mice and rats. If mice or rats are in or around the house,
snakes will be attracted by their presence.
• Close holes in the ground or walls in or around the house. These may
be used by snakes as hiding places or to enter the house or may be the
home of mice or rats.
• Wearing long clothes and boots (if practical) may help to protect from
envenoming if bitten.
• Always use a torch or other light sources while walking in the dark of night.
71
• Be careful while working on stones or wood as snakes may be hidden
under rocks and branches or fallen trees.
• Children should be advised not to play in localities where snakes are
known to be especially common.
• Try to know the species of snake that are venomous and non-venomous
in the area where you live.
• Avoid sleeping on the ground – indoors as well as outdoors. Many
snake bites, especially by kraits, occur on people who sleep on the
ground at night.
• Proper use of a mosquito net may help to prevent snake bites. If the
mosquito net is well tucked under the mattress and has no holes,
snakes cannot get onto the sleeping place.
• Look under your pillow and blankets before going to bed - sometimes
a snake is hidden there.
• Use beds on poles and do not put the bed next to structures that snakes
could use to climb up, like house walls made of straw, bamboo or wood.
Fig. 106. Bilateral ptosis in neurotoxic snake bite envenoming. Due to the effects of the snake venom,
the patient is unable to lift the eyelids. She also can no longer fully open the mouth because her jaw
muscles are paralysed. This also affects the ability to speak.
72
S.K. Sharma
• If you are sleeping under a tent, its door should be closed properly.
S.K. Sharma
S.K. Sharma
Fig. 107. Consequences of the use of a tight tourniquet. Many people tightly apply ropes or other
materials to a bitten limb hoping to slow down the spread of venom. However, this practice in itself can
cause severe damage even in the absence of venom, by obstructing the blood flow, and may result
in the need for amputation. It also aggravates the local destruction of tissues by cobra, viper and pit
viper venoms.
Fig. 108. Sequelae of local snake bite envenoming. Cobra, king cobra, pit viper and Russell's Viper
venoms are known to cause significant local envenoming that may lead to necrosis and loss of
tissues. Contractures of digits as shown here or the amputation of fingers, toes or entire limbs are the
most common long-term consequences. Permanent disability following snake bite envenoming puts
a heavy burden on families in the rural areas. Early and effective medical treatment can reduce the
extent and severity of local snake bite envenoming.
73
H.S. Bawaskar
Fig. 111. "Broken neck" sign observed in a girl bitten
by a snake. Envenoming by cobras and kraits (in
some areas also by Russell's Viper) frequently
leads to progressive descending paralysis. Looking
for the broken neck sign, which is caused by
paralysis of the neck flexor muscles, should be part
of the routine clinical assessment of patients. In this
case from India, the envenoming was caused by
Russell's Viper (Daboia russelii).
74
D.A. Warrell
Fig. 109. Mild local swelling after the bite of a
green pit viper near Damak, Jhapa, Nepal. In
Nepal, painful swelling of the bitten body part
is a characteristic feature of envenoming by pit
vipers and vipers, and by cobras.
Fig. 110. Gum bleeding after snake bite. In Nepal,
coagulation defects and spontaneous bleeding
have been observed following bites by pit vipers
like the Mountain Pit Viper (Ovophis monticola).
However, this is also characteristic after bites by
Russell's Viper (Daboia russelii), here in a case from
India, which is a comparatively rare snake in Nepal.
D.P. Pandey
U. Kuch
Fig. 112. Envenoming by kraits and cobras
frequently results in respiratory paralysis.
In these cases, early assisted ventilation is
life-saving. Here it is performed manually using
an Ambu bag on a paralysed patient bitten by a
Common Krait (Bungarus caeruleus).
Selected additional information resources
Guidelines for the Management of Snake Bites (South and SouthEast Asian regions), published by the World Health Organisation - Regional
Office for South-East Asia (WHO/SEARO). A free download of the 2010
edition by D. A. Warrell is available from:
http://www.searo.who.int/catalogue/2005-2011/pdf/bloodsafety/guidelines_snakebites.pdf
VAPAGuide - Emergency Guide to Venomous and Poisonous Animals.
This free internet-based resource by T. Junghanns and M. Bodio on
venomous and poisonous animals and the clinical management of
envenoming and poisoning is available at:
http://www.vapaguide.info
Clinical Toxinology Resources Website. This internet-based resource
on clinical toxinology and venomous and poisonous animals is maintained
by J. White and colleagues at the Toxinology Department of the Women’s
& Children’s Hospital (WCH) in Adelaide, Australia, and is available at:
http://www.toxinology.com
Snake bite in South Asia: a review. This review article by E. Alirol, S. K.
Sharma, H. S. Bawaskar, U. Kuch and F. Chappuis covering 122 literature
references on snake bite in South Asia is available free from the web site
of the journal PLoS Neglected Tropical Diseases:
http://www.plosntds.org/article/info%3Adoi%2F10.1371%2Fjournal.pntd.0000603
WHO Guidelines for the Production, Control and Regulation of
Snake Antivenom Immunoglobulins. These World Health Organisation
guidelines and additional important information are available at:
http://www.who.int/bloodproducts/snake_antivenoms/en
WHO Database on Snake Antivenoms and Venomous Snakes. This
searchable database provides information on existing snake antivenom
immunoglobulin products and snakes of medical importance, distribution
maps and photographic references. It is available at:
http://apps.who.int/bloodproducts/snakeantivenoms/database/default.htm
Global Snake Bite Initiative (GSI)
http://www.snakebiteinitiative.org
75
International Society on Toxinology (IST)
http://www.toxinology.org
Snakes of India – The Field Guide by R. Whitaker and A. Captain. Draco
Books (Chennai); 2008, 495 pp.
Snake bite Management Guideline (in both Nepali and English) by
K. B. Shah, J. M. Shrestha and C. L. Thapa. HMG's Ministry of Health,
Department of Health Services, Epidemiology & Disease Control Division
(Kathmandu); 2003, 56 pp.
Amphibians and Reptiles of Nepal by H. H. Schleich and W. Kästle
(Ed.). A.R. Gantner Verlag (Ruggell); 2002, 1295 pp.
N.L. Orlov
Herpetofauna of Nepal: A Conservation Companion by K. B. Shah and
S. Tiwari. IUCN - The World Conservation Union (Kathmandu); 2004, VIII +
237 pp.
Fig. 113. MacClelland's Coral Snake (Sinomicrurus macclellandi univirgatus), adult female from Rakse,
Ilam, Mechi, Nepal, 2300 m above sea level.
76
Motorcycle volunteer programme to minimize
deaths related to snake bite
The motorcycle volunteer programme is a network of motorcycle
owners in remote lowland villages of eastern Nepal. Volunteers serve
around the clock transporting suspected or proven snake bite victims
as quickly as possible to the nearest hospital or healthcare centre
where facilities for snake bite treatment exist. The snake bite victim
is held firmly between the motorcycle driver and an assistant pillionrider to prevent the patient falling from the vehicle during transport
(see below). This programme precedes awareness programmes and
emphasizes earlier transport of the victim to an appropriate snake bite
treatment centre by motorcycle. It also provides educational messages
and simple slogans such as
"bitten by snake – catch motorcycle volunteers – reach nearby
snake bite treatment centre – save life!"
It helps in minimizing snake bite related deaths.
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